Rust preventive compositions containing acid polyester succinates



States The present invention relates to use of chemical compounds whioh are oil soluble, particularly in petroleum oil fractions and which exhibit rust preventive properties towards metals, especially steel and ferrous iron surfaces. The simplest and most convenient method of developing a rust protecting film on the metal surface is to dissolve one of the preferred rust preventive compounds disclosed herein in a suitable petroleum base carrier such as motor gasoline, aviation, gasoline, jet fuel, turbine oils and the like. Inasmuch as the lead salts of compounds of the preferred class of compounds do not form, or if formed are completely soluble in the petroleum fraction employed, the compounds hereinafter described may be used in leaded fuels. Thus the fuels mentioned and containing the preferred rust preventive compound may be employed as a fuel in internal combustion engines, jet engines and the like and the various parts and fittings of the engines are not damaged by deposition of insolubles and are protected from rusting. In particular fuel injeotion systems are not clogged or damaged by fuels containing the new *adjuvants. Moreover, no insoluble alkaline earth salts are formed by reaction of sea water with the preferred class of compounds, thereby permitting the use of storage tanks previously containing a sea water ballast to be loaded with an oil fraction or a fuel treated with one of the preferred rust preventive compounds, as well as enabling storage of the treated fuel over sea water without serious loss of inhibitor taking place.

This application is a division of parent application Ser. No. 678,525, filed August 16, 1957, now Patent No. 3,045,042.

The preferred class of chemical compounds hereinafter described and set forth as rust preventive compounds are the partial esters of an alkyl or alkenylsucoinic anhydride and preferably are the products obtained by the reaction of one molar equivalent of a polyhydric alcohol with two molar equivalents of the anhydride. Struoturally the preferred class of rust preventive compounds are most conveniently represented by the formula:

wherein of the radicals R and R, one is hydrogen and the other is selected from a group comprising alkyl and alkenyl radicals preferably containing from 8 to 15 carbon atoms and R" is the residue of the polyhydric alcohol which generically may contain oxygen, sulfur or nitrogen in the chain as well as ester substituents, and preferably contains from 3 to 6 carbon atoms. The integer n represents a number from 1 to 4 to indicate that within the purview of the invention are included the derivatives of diols, triols and other polyhydroxy compounds.

A typical procedure for the preparation of the chemical rust preventive compound employed in the present invention is the following which is illustrative only as a non atent Patented Jan. 7, 1964 "ice The following are illustrative of products obtained by heating one molecular proportion of a dihydric alcohol with two molecular proportions of an alkenylsuccinic anhydride. In each case the alkenylsucoinic anhydride used was dodecenylsuccinic anhydride prepared from propylene tetramer and maleic anhydride and the product was prepared from the intermediate by heating at about C. for the indicated times, generally without a solvent or diluent although in a few cases the reaction was carried out by heating in kerosene.

Neutralization Time Number Example Alcohol of Heating, hrs.

Found Cale.

Ethylene glycol 15.0 199 188. 5 Propylene glycoL 23.0 210 184 1 4-butane dlol 4.0 181 1 3-butane (1101 9.0 178 180 2,3-butane dlol 16. 5 194 180 2-butene-1,4-diol 14. 0 190 181 Diethylene glycol. 4. 0 183. 4 175 2,2-thio diethanoL- 11.0 187 171 1,5-pcntane (liol 10. 0 184 176 1,4-pentane diol 8. 0 189 176 Neopentyl glycol.. 15.0 185 176 1,6 hcxane diol 4.0 176 172 2-methyl-2,4-pentanc 18. 0 250 172 Methyl-1,3-pentanc diol 25.0 187 172 Dipropylene glycol 9.0 175 168 Triethylene glycol 4. 5 183 163 2,2,4-trimcthyl-1,3-pentane 15. 0 165 165 2-Ethylhexanc diol-1,3 13.0 181 165 2,2-dicthylpropane diol-1,3 9.0 159 169 2,S-dimethylhexane-Z,5-diol 24. 5 271 165 Phenyl-1,2-ethane di0l 13. 5 188 167 2ethyl-2-butylpropane d 10. 0 161 162 3,6-dimethyloctane 3,6-diol 18. 5 263 158 Polyethylene glycol 200 4.0 153 Polyethylene glycol 400 4. 0 126 121 Polypropylene glycol 150 19.0 179 164 Polypropylene glycol 425 15.0 129 118 3-methyl-l ,5-pentane diol 10.0 174 172 'lrimcthylenc glycol 11. 0 210 184 All of the foregoing products were soluble in petroleum ether except the products from polyethylene glycol 20 0 and polyethylene glycol 406 which were partially soluble. The numbers following the glycol polymers indicate the molecular weight.

Using the same dodecenylsuccinic anhydride as employed in t e above examples, further illustrative examples 3 are set forth below in which the ratio of the reactants varied. All these products were prepared by heating at approximately 95-105 C. for the times indicated. TPSA means tetrapropenyl (dodecenyl) succinic anhydride.

The various chemical products of the class described were tested to determine their solubility in petroleum oil' by adding 1% by weight of the chemical product to 100 parts of petroleum ether and stirring. If any residue is observed, the product is indicated as insoluble. All of the products in the foregoing table were soluble in petroleum ether and gasoline.

In order to obtain products which do not tend to form permanent emulsions nor to precipitate alkaline earth and lead salts, the alkenyl or alkyl group is desirably within the range of 8-15 carbon atoms. However, excellent rust inhibiting properties are obtained from reactants containing alkyl and alkenyl groups outside this range. The following are illustrative of products in which the alkenylsuccinic anhydride varied. These products were prepared by heating one molecular proportion of a dihydric alcohol with two molecular portions of the alkenyl'succinic anhydride at 95-l25 C.

NOSA=n-etenylsuceinic anhydride.

NDDSA=n-dodecenylsuceinie anhydride. HDSA=n-hexadecenylsuceinic anhydride. OD SA=n-octadeeenylsuceinic anhydride.

All of the products in the foregoing table were soluble in petroleum ether except the reaction product of 1,4-butane diol and NOSA which was partially soluble.

The rust preventive properties of the chemical products were observed by carefully cleaning and polishing in the well recognized manner for performing this test test strips of steel 3 /2" X /s" x having an S.A.E. grade designation 1020 and vigorously shaking each specimen in 7 cc. of petroleum ether containing the desired concentration or concentrations (from 5 to 20 parts per million of solvent) of the rust inhibitor. After standing f or onehalf hour, 2 cc. of distilled water are added and the sample is reshaken. The strip is allowed to stand in 'the wet petroleum ether at room temperature for about three hours, is then removed and visually inspected for rust. The results of the tests on various products of the present inventionare set forth in the following table. The example numbers correspond to those of the products identified in the foregoing tables and will serve to identify the particular material tested.

Steel Strip Rust Example Hydroxy Reactant 20 ppm. 10 ppm. 5 p.p.m.

Ethylene glycol none. light. light. Propylene glycol. trace nonc Do. 1, it-butane diol..- none. trace. 1, 3-butane diol. lo-.... none. none 2, 3-butane diol. -.do... -..do Do. 2-butene-1, 4-diol. -do -do-.... trace Diethylene glycol. trace-. .do... none 2, 2-trio diethanol none.-. light...- light. 1, 5-pentane dioL- trace.. nonenone. 1 4-pentane diol.. rust Neopentyl glycol. none. none. light. 1, (i-hexane diol do trace. 2-methyl-2, 4-pentane diol--. do....- none I Do. Methyl-1-1,3-pentane diol-.. do..... tracc.... light Dipropylene glycol do....- none. D0- Triethyleue glycol do none 2, 21, 4-trimethyl-1, 3-pentane do-..-- light... rust iol. 2-ethylhexane diol-1, 3 rust. 2, 2-diethylpropane diol l, 3.. none. none. 2, 5-dimethylhexane-2, 5-diol rust-.. rust. Phenyl-l, 2-ethane diol. none. none. 2-ethyL2-butylpropane diollight. light 3, S-dimethyloctane 3, G-diol. rust rust. Polyethylen'ge glycol 200. none. Do. Polyethylenge glycol 400... clo-.- trace. Polypropylenge glycol 150..- nonelight. rust. Polypropylene glycol 425-... -..do..... none. Do. 3-methyl 1, 5-pentane diol. light.. rust Triinethylene glycol.--. -.do-... none-. none. 1, 2, l -butane trioL- do..-. trace. Castor oil light. Trieth anolamine. none. Glycerol .-.do.. none. 0. Pentiaerythritol trace- 2-methyl-2, i-peutane diol.

Various other tests employed in the art were also utilized in the further testing of chemical products of the present invention. A description of these tests and the results obtained follow. I

Water tolerance test.-Tl1is test is used to evaluate the emulsion characteristics of the rust inhibited petroleum fraction, such as a petroleum fuel, as set forth in A.S.T.M. D1094-53. The apparatus consists of a cc. glass stoppered graduated cylinder, which after thorough cleaning is rinsed thoroughly with distilled water and stored completely full of distilled water until used in a test. The water is removed and 8000. of iso-octane containing 20 parts per million of the inhibitor under test is placed in the graduate and 20 cc. of distilled water added thereto and the mixture is shaken vigorously at room tempera ture for 2 minutes. The mixture is then allowed to stand on a vibration-free surface for 5 minutes whereupon the volume of the aqueous layer and the amount of emulsion, if any, are recorded. In order to pass the test, the fuel shall separate sharply from the water and there shall be no evidence of an emulsion, precipitate or suspended matter within or upon either layer. Neither layer shall have changed more than 1 cc. in volume.

Sea water reaction test.This test is designed to determine the solubility of the alkaline earth salts of rust inhibitors. Synthetic sea water was prepared according to the method set forth in Procedure B, A.S.T.M. D655-53T. The method consists in adding 250 cc. of n-heptane containing about 200 ppm. of the material to be tested and 25 cc. of synthetic sea water to a 500 cc. 3-neck flask equipped with stirrer and reflux condenser and stirring for 30 minutes at room temperature. Agitation was stopped and when motion had ceased the interface was examined for scum and the walls of the flask examined for precipitate of which there shall be none.

Lead salt test.-This test is designed to indicate the possibility of precipitate from the use of rust inhibitor in a leaded gasoline. In this test, an ionizable lead salt is added to assure a concentration of lead ion. The test solution is prepared by dissolving 25 parts of lead naphthenate in 2500 parts of a regular gasoline and the solution is filtered through a double thickness of filter paper and then through a layer of fullers earth. Thereupon 100 cc. of the test solution is added to a 500 cc. 3-neck flask equipped with a stirrer and air condenser. Agitation is star-ted :and the rust inhibitor under test is added dropWi-se until about 0.5 gram has been added whereupon agitation is continued for an hour at room temperature and the mixture is examined for haziness or insolubles with the aid of a flashlight. To pass the test there shall be no more haze than is exhibited by use of a blank test with no inhibitor present. The results obtained from the above-described tests are set forth in Table I wherein various reaction products of an alkenylsuccinic anhydride with the diol indicated in the table are shown.

The rust preventing characteristics of steam turbine oil in the presence of water was determined by following A.S.T.M. Test D665-53T, Procedure B thereof. The oil employed was a base stock in commercial use for the formulation of stream turbine finished lubricants and of course contained no inhibitor of any kind. In this test, the reaction product comprising the partial ester from tetrapropenylsuccinic anhydride with the indicated diol yielded the results shown in Table II.

Table I A.S.T.M. Rust Test Example Diol Propylene glycol light- 1,4-butaue diol-- trace moderate.

2,3-butane diol.. clean clean.

2-rnethyl-2,4-pentane none light.

diol.

Castor oil rust Triethanolamine none none light.

Glycerol trace trace moderate.

As was shown in the reaction equation set forth illustrating the formation of the preferred rust preventive compounds, no water is evolved in the reaction of the diol and succinic anhydride derivative. The products, while containing carboxyl groups, are weak acids and do not liberate hydrogen on contact with ferrous metal or other metallic fittings used in a motor or engine. It is apparent that a wide range of products are included in the invention. Other alkylsuccinic anhydrides have been reacted with diols as described. Thus, octenylsuccinic anhydride, dodecenylsuccinic anhydride, hexadecenylsuccinic anhydride and octadecenylsuccinic anhy'dride were reacted with 1,4-butane diol.

It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departtures from the spirit and scope of the invention.

What is claimed is:

l. A rust preventive composition consisting essentially of a major proportion of a solvent carrier having in solution therein a minor but rust inhibiting proportion of a partial ester having the general formula wherein of the radicals R and R one is hydrogen and the other is selected from a group consisting of alkyl and alkenyl radicals containing from 8 to 15 carbon atoms, R is a residue of a polyhydric alcohol containing from 3 to 6 carbon atoms and n is an integer at least one but less than five.

2. A rust preventive composition consisting essentially of a major proportion of a mineral oil fraction having in solution therein a minor but rust inhibiting proportion of a partial ester having the general formula wherein of R and R one is hydrogen and the other an alkenyl radical containing 8 to 15 carbon atoms, R" is a residue of a polyhydric alcohol and n is an integer at least one but less than four.

3. A rust preventive composition consisting essentially of a major proportion of gasoline having in solution therein a minor but rust inhibiting proportion of a partial ester having the general formula wherein of R and R one represents hydrogen and the other an allcenyl group of 8-15 carbon atoms and R is an alkylene group 0 f3-6 carbon atoms.

4. A rust preventive composition consisting essentially of a major proportion of jet engine liquid fuel having in solution therein a minor but rust inhibiting proportion of a partial ester having the general formula wherein of R and R one represents hydrogen and me other an alkenyl group of 8-15 carbon atoms and R is an alkylene group of 3-6 carbon atoms.

7 5. A rust preventive compos'ition consisting essentially of a major proportion of petroleum liquid fuel containing tetraet hyl lead having in solution therein a minor but rust inhibiting proportion of a partial ester having the general 1 wherein of R and R one represents hydrogen and the 5 other an .alkenyl group of 845 carbon atoms and R" is an alkylene group of 3-6 carbon atoms.

6. A rust preventive composition consisting essentially of a major proportion of mineral oil lubricant having in solution therein a minor but rust inhibiting proportion of a partial ester having the general formula wherein of R and R one represents hydrogen and the other an alkenyl group of 815 carbon atoms and R is an alkylene group of 3-6 carbon atoms.

7. A rust preventive composition consisting essentially of a major proportion of. a mineral oil fraction having in solution therein a minor but rust inhibiting proportion of a partial ester having the general formula wherein of R and R one represents hydrogen and the other a branched chain dodecenyl group.

8. A rust preventive composition consisting essentially of a major proportion of a mineral oil fraction having in solution therein a minor but rust inhibiting proportion of a partial ester having the general formula wherein of R and R one represents hydrogen and the other a branched chain dodecenyl group.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A RUST PREVENTIVE COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF A SOLVENT CARRIER HAVING IN SOLUTION THEREIN A MINOR BUT RUST INHIBITING PROPORTION OF A PARTIAL ESTER HAVING THE GENERAL FORMULA 